As a field emission type cold cathode electron source (which will be referred to as an “electron source” hereinafter), there is a so-called spint type electron source or a so-called planar multi-layered type electron source having a configuration in which a lower electrode, a metal or a semiconductor thin film, an insulating layer, and an upper electrode are sequentially superimposed.
The former spint type electron source has a lower electrode in which many small conical tips (emitters) usually formed of molybdenum are arranged, an upper electrode in which hole portions from which end portions of the tips are exposed are arranged, and an insulating portion formed between the lower electrode and the upper electrode. The spint type electron source is configured to emit electrons through the hole portions by applying a positive voltage to the upper electrode with respect to the lower electrode. This spint type electron source is an electron source that currently has the highest percentage of completion.    Patent Reference 1: Japanese Patent Application Laid-open No. 2000-106101    Patent Reference 2: Japanese Patent Application Laid-open No. 2000-100358However, as to the spint type electron source, since the electron source including the small conical tips is formed by a fine processing technology, its manufacturing process is complicated, and the spint type electron source is hard to be formed to have a large area and has an inconvenience that its manufacturing cost is very high.
Further, the planar multi-layered type electron source can be readily manufactured as compared with the spint type electron source, but it requires various kinds of lamination processes, and it cannot be necessarily easily manufactured.